Novel polymer composition

ABSTRACT

A polymer composition wherein an inorganic substance and an organic polymer are firmly consolidated, which is characterized by being produced by polymerizing a vinyl monomer susceptible to radical polymerization in a polymerization system containing a dispersed inorganic substance in the presence of at least one monomer selected from sulfonic acid monomers, sulfonate monomers, or carboxylic acid monomers represented by the general formula [I] ##STR1## wherein R 1  is a hydrogen atom, alkyl group having 1 to 20 carbon atoms, phenyl group, derivative of phenyl group, or halogen atom, X is CONH, ##STR2## COO(CH 2 ) m  or (CH 2 ) n  (wherein R 2  and R 3  are each a hydrogen atom or alkyl group having 1 to 15 carbon atoms, R 4  is an alkylene group having 1 to 15 carbon atoms, m is an integer of 1 to 20, and n is an integer of 0 to 20), and Y is a hydrogen atom, ammonium radical, or an alkali metal atom, or by the general formula [II] ##STR3## wherein R 5  is a hydrogen atom, alkyl group having 1 to 15 carbon atoms, COOZ, halogen atom, phenyl group, or derivative of phenyl group, R 6  is a hydrogen atom, alkyl group having 1 to 15 carbon atoms, COOZ, halogen atom, phenyl group, or derivative of phenyl group, R 7  is a hydrogen atom, alkyl group having 1 to 15 carbon atoms, halogen atom, phenyl group, or derivative of phenyl group, and Z is a hydrogen atom, ammonium radical, or alkali metal atom, or by the general formula [III] ##STR4## wherein R 8  and R 9  are each a hydrogen atom, alkyl group having 1 to 15 carbon atoms, halogen atom, phenyl group, or derivative of phenyl group.

This invention relates to a novel polymer composition in which aninorganic substance and an organic polymer are firmly consolidated.

For the polymerization of a vinyl monomer, there have been known variousmethods such as radical polymerization, ionic polymerization, andcoordination polymerization. However, polymerization methods simple andeasy to operate on commercial scale are rather few, because, forinstance, these methods require some polymerization initiator such asperoxides, persulfates or azo compounds in radical polymerization; theanionic polymerization requires moisture control. Also, there have beenreported noncatalytic polymerization methods without employing initiatorin Makromol. Chem. (CME), 180 (11), 2649 (1979), Eur. Polymer J. (GBR),15 (2), 153 (1979), and J. Appl. Polym. Sci, (USA), 25 (1), 89 (1980),but these methods are not practicable on commercial scale production.

Under the above-mentioned circumstances, the present inventors conductedextensive studies and, as a result, accomplished this invention which ispredicated upon the discovery that when a vinyl monomer susceptible toradical polymerization is contacted with an inorganic substance, used asa third component, in the presence of a specific sulfonic acid monomer,sulfonate monomer, or carboxylic acid monomer, the polymerizationactivity of the vinyl monomer is markedly increased and there is formeda novel polymer composition in which the inorganic substance and theorganic polymer are firmly consolidated to a degree as high as neverbeen reached by the conventional method.

Heretofore, a great deal of efforts have been directed to thedevelopment of composite materials in which two or more componentmaterials are combined in such a manner that the characteristics of thecomponent materials are mutually compensated or enhanced to create a newuseful function. Regarding the composite formation between an organicpolymer and an inorganic powder useful as a filler for the former,improvements in a wide range of performance characteristics such asmodulus of elasticity, heat distortion temperature, electric properties,and the like were reported in Plastics Eng. 30, [9], 30 (1974) and Tech.Conf. Soc. Plast. Eng. (USA), 37th, 492. However, since in the case ofthe above-mentioned reports the components are of quite differentproperties to each other, they lack interfacial affinity such ascompatibility, adhesiveness, or the like and the assembly has afundamental defect of exhibiting only insufficient composite effect,accompanying even a decline in some characteristics of the resin, suchas toughness.

To improve the above defect, attempts have heretofore been made toincrease the interfacial affinity between the organic polymer and theinorganic substance by a mechano-chemical method reported in PlasteKautschuk (DDR), 26 (3), 134 (1979), in which the inorganic substance isground in the presence of a reactive monomer to graft the organicpolymer, or by a radiation method reported in Polymer Sci., USSR, 8, 24(1966); SPE Tech. Pap. Annu. Tech. Conf. (Soc. Plast. Eng.), 23, 333(1979); "Kinzoku Hyomen Gijutsu" (Metal Surface Technology), 29, 529(1978), in which an inorganic substance is irradiated with a high-energyradiation to be grafted with an organic polymer. These methods, however,require a grinding step or installation of a radiation equipment,resulting in complication of the manufacturing process and increase ofthe manufacturing cost, and present difficult problems for thepracticability of the process.

This invention has solved the above difficult problems. According tothis invention, there is provided a polymer composition wherein aninorganic substance and an organic polymer are firmly consolidated,which is characterized by being produced by polymerizing a vinyl monomersusceptible to radical polymerization in a polymerization systemcontaining a dispersed inorganic substance in the presence of at leastone monomer selected from sulfonic acid monomers, sulfonate monomers,and carboxylic acid monomers represented by the general formula [I]##STR5## wherein R₁ is a hydrogen atom, alkyl group having 1 to 20carnon atoms, phenyl group, derivative of phenyl group, or halogen atom,X is CONH, ##STR6## COO(CH₂)_(r) or (CH₂)_(n) (where R₂ and R₃ are eacha hydrogen atom or alkyl group having 1 to 15 carbon atoms, R₄ is analkylene group having 1 to 15 carbon atoms, m is an integer of 1 to 20,and n is an integer of 0 to 20), and Y is a hydrogen atom, ammoniumradical, or an alkali metal atom, or by the general formula [II]##STR7## wherein R₅ is a hydrogen atom, alkyl group having 1 to 15carbon atoms, COOZ, halogen atom, phenyl group, or derivative of phenylgroup, R₆ is a hydrogen atom, alkyl group having 1 to 15 carbon atoms,COOZ, halogen atom, phenyl group, or derivative of phenyl group, R₇ is ahydrogen atom, alkyl group having 1 to 15 carbon atoms, halogen atom,phenyl group, or derivative of phenyl group, and Z is a hydrogen atom,ammonium radical, or alkali metal atom, or by the general formula [III]##STR8## wherein R₈ and R₉ are each a hydrogen atom, alkyl group having1 to 15 carbon atoms, halogen atom, phenyl group, or derivative ofphenyl group.

When polymerization of a vinyl monomer is carried out in the presence ofan acid alone under such temperature conditions that no thermalpolymerization will take place, the monomer conversion is generally at avery low level even after a polymerization time extending to severaldays, whereas, according to this invention, the addition of an inorganicsubstance, as the third component, brings about very specificpolymerization activity and there is formed in several hours apractically valuable polymer with a high conversion, which is veryclean, being free from the deposit of cullets formed by the gas phasepolymerization.

Another feature of this invention is that the interaction between thesurface of an inorganic substance and the polymer formed according tothis invention is a firmly consolidated union beyond the adhesion in thesense of simple adsorption. It is a further feature that the polymerwhich is formed is a high-molecular one. As is reported in ModernPlastics, Jan., 143 (1968), in the composite formation between aninorganic substance and a material with a greatly different modulus ofelasticity such as, for example, an ordinary thermoplastic resin, ahighly reinforced polymer composition is formed when there is present atthe interface of both materials a high-molecular polymer which is of thesame type as said resin and has a modulus of elasticity intermediatebetween both materials to secure smooth stress transfer. An example ofthe embodiment of this invention is described below.

Under the conditions such that no thermal polymerization will takeplace, a sulfonic acid monomer, sulfonate monomer, or carboxylicacid-type monomer is added with stirring to a suspension of an organicvinyl monomer and an inorganic substance in an aqueous medium to causethe polymerization in an aqueous heterogeneous system. In this manner itis possible to cover the surface of the inorganic substance uniformlyand solidly with the polymer of said vinyl monomer in a predeterminedtime with a high conversion of monomer. Although it is indispensable toallow the above three components to contact with each other, yet it isnot necessary to add the three components at the same time. Forinstance, when an inorganic substance pretreated with a sulfonic acidmonomer, sulfonate monomer or carboxylic acid-type monomer is used, asimilar polymer composition is obtained without adding fresh monomerduring the polymerization of a vinyl monomer.

It is known that a polymer composition similar to that described aboveis obtained in the presence of a hydrogensulfite ion [Chemistry andIndustry, 3 Aug., 619 (1974); Die Angewandte Makromoleculare Chemie, 53,65 (1976); Japanese Patent Publication Nos. 46,552/76, 48,174/76,13,499/77, 28,147/77, 28,148/77, 29,789/77, 31,912/77, 8,349/78 and9,420/80]. Such a process, however, has inevitable disadvantages for itscommercialization in that the resulting polymer is covered with a greatdeal of cullets formed by the gas phase polymerization and, moreover, isin the form of fine granules which are difficult to wash or recover. Tothe contrary, in the present process, by the use of a specific sulfonicacid monomer, sulfonate monomer, or carboxylic acid-type monomer, thereare established the polymerization conditions for the formation of aclean polymer substantially without formation of cullets; it is also asurprising fact that because of its strong tendency to form secondaryagglomerates, the resulting polymer composition is easily treated in thesubsequent steps of the operation such as washing and recovering.Although a specific carboxylic acid-type monomer exhibits anindustrially favorable ability to produce a polymer composition, havinga desirable tendency to form secondary agglomerates substantiallywithout deposition of cullets, yet a sulfonic acid monomer or sulfonatemonomer is preferred because of a higher degree of monodispersion in theparticle size of resulting polymer composition.

The specific sulfonic acid monomer, sulfonate monomer, or carboxylicacid monomer used in this invention are those which have a sulfonic acidgroup or a carboxylic acid group as the active site to bring about thepolymerization activity and, in addition, a double bond as the activesite to develop firm consolidation between the inorganic substance andthe polymer which is formed. All compounds having a structure whichinvolves those functional groups are suitable. Examples of suitablesulfonic acid monomers or sulfonate monomers include2-acrylamido-2-methylpropanesulfonic acid (AMPS), sodium2-methacryloylethanesulfonate (SEM.Na), sodium3-methacryloylpropanesulfonate (SPS), sodium 2-propenesulfonate (NaAS),and sodium 2-methyl-2-propenesulfonate (NaMS). Of these, especiallypreferred are AMPS containing an amide linkage, and SEM.Na and SPS bothcontaining an ester group because of their distinctive ability to formsecondary agglomerates and superior polymerization activity. Examples ofsuitable carboxylic acid-type monomers include acrylic acid, methacrylicacid, crotonic acid, tiglic acid, cinnamic acid, maleic anhydride, andcitraconic anhydride. Of these, acrylic acid, methacrylic acid andcrotonic acid are especially preferred because of their desirableability to form secondary agglomerates and of their high polymerizationactivity.

The inorganic substances used in this invention are elements of GroupsI, II, III, IV, V and Transition Group of the periodic table and theiroxides, hydroxides, chlorides, sulfates, sulfites, carbonates,phosphates, silicates, mixtures thereof, and double salts thereof. Amongthe inorganic substances, particularly preferred are calcium sulfite,calcium sulfate, silicon dioxide, titanium oxide, antimony trioxide,talc, clay, aluminum oxide, calcium carbonate, carbon black, graphite,carbon fiber, glass fiber, nickel powder, iron powder, zinc powder,copper powder, ferric oxide, zinc oxide, aluminum hydroxide, magnesiumoxide, and calcium hydroxide, because of their outstanding ability toactivate the vinyl monomer and to form a firm union with the polymer.

The vinyl monomers suitable for use in this invention include all of thevinyl monomers susceptible to radical polymerization. Above all, methylmethacrylathas a specifically high polymerization activity and, inaddition, is desirable for the consolidation with inorganic substances.When a mixture of two or more monomers is used, it is preferableparticularly for the polymerization activity to use methyl methacrylateas one of the component monomers.

According to this invention, the concentration of a sulfonic acidmonomer, sulfonate monomer, or carboxylic acid-type monomer is about0.05 to 100%, preferably 0.1 to 50%, most preferably 0.5 to 30% byweight based on the sum of inorganic substance and monomer. In most ofthe cases, with the increase in the quantity of the component monomer,it is preferable to increase the amount of a sulfonic acid monomer,sulfonate monomer, or carboxylic acid-type monomer. As compared with thecase of an inorganic substance used as catalyst, the weight ratio of amonomer or a monomer mixture to the inorganic substance is far smallerand, as far as such condition is maintained, can be varied within a widerange of from about 500:1 to 1:5, usually from 250:1 to 1:5, preferablyfrom about 50:1 to 1:1. The amount of water is 1% to severalhundred-fold, preferably from 10% to ten-fold based on total weight ofinorganic substance and monomer.

The polymerization is carried out under an atmosphere of inert gasessuch as nitrogen and at a temperature of from 10° to 100° C., preferably20° to 80° C. Although the most suitable polymerization temperature forparticular cases is suitably selected depending upon the type of vinylmonomer, it is important to conduct the polymerization at a temperatureat which the thermal polymerization takes place merely to a negligibleextent. If the polymerization is carried out at a temperature at whichan appreciable degree of thermal polymerization will take place, theintegrity and the uniformity of the resulting composite will behindered. The reaction time is from 30 minutes to about 15 hours. Theresulting composite can be dried at a temperature in the range of about10° to 300° C., preferably from about 50° to 200° C.

Further, the interaction between the inorganic substance and the polymerformed according to this invention is very strong exceeding the adhesionin physical sense such as that resulting from adsorption or by van derWaals' force, as evidenced by the large amount of unextractable polymerremaining after extraction with a good solvent for the polymer.

The present composition is useful as a reinforcing filler for organicpolymers and as a thickening agent or a dispersant for coatingcompositions.

The invention is further illustrated below in detail with reference toExamples.

EXAMPLE 1 AND COMPARATIVE EXAMPLES 1 TO 6

In a 500-ml four-necked flask provided with a cooler, nitrogen inlet,stirrer and a thermocouple for detecting the intermal temperature, 38.7g of calcium sulfite hemihydrate, used as the inorganic substance, wassuspended in 270 ml of deionized water to form a dispersion. Afterflushing the flask with nitrogen for 30 minutes, 30.0 g of MMA, used asthe vinyl monomer, was added to the dispersion with vigorous stirringunder a nitrogen stream. The reactant mixture was heated to 50° C. in awater bath. After confirming the uniform dispersion of the addedmonomer, to the dispersion was added slowly a solution of 6.5 g ofSEM.Na, used as the sulfonate monomer, dissolved in 10 ml of deionizedwater. The mixture was maintained at the same temperature to allow thepolymerization to proceed for 8 hours. After completion of thepolymerization, about 2 g of the reaction mixture was withdrawn as asample. The sample was tested for the conversion by determining theremained unreacted monomer by gas chromatography using dioxane asinternal standard.

For comparison, similar polymerization procedure and similar evaluationtests on the polymerization mixture to those described above wererepeated in the cases where the addition of the inorganic substance,sulfonic acid monomer, or sulfonate monomer was omitted and in the caseswhere ethanesulfonic acid, which is a saturated sulfonic acid, or anaqueous sulfurous acid solution was added.

The results obtained were as shown in Table 1, wherein all parts are byweight.

                                      TABLE 1                                     __________________________________________________________________________                                  Inorganic       Nature of                              Compound containing sulfonic group (parts)                                                           substance                                                                          Vinyl      polymerizate*.sup.4                                 Ethane-                                                                            Aqueous                                                                            (parts)                                                                            monomer                                                                            Deionized                                                                           Cullet                                                                            Secondary                                                                           Conversion                                sulfonic                                                                           sulfurous                                                                          Calcium                                                                            (parts)                                                                            water deposi-                                                                           agglomera-                                                                          of monomer                   SEM.Na                                                                             SPS AMPS                                                                              acid acid*                                                                              sulfite*.sup.2                                                                     MMA*.sup.3                                                                         (parts)                                                                             tion                                                                              tion  (%)                   __________________________________________________________________________    Example 1                                                                            6.5  --  --  --   --   38.7 30.0 280   ⊚                                                                  ⊚                                                                    82.6                  Comparative                                                                          6.5  --  --  --   --   --   30.0 280   --  --    7.0                   Example 1                                                                     Comparative                                                                          --   7.0 --  --   --   --   30.0 280   --  --    7.3                   Example 2                                                                     Comparative                                                                          --   --  6.6 --   --   --   30.0 280   --  --    7.6                   Example 3                                                                     Comparative                                                                          --   --  --  --   --   38.7 30.0 280   --  --    0.0                   Example 4                                                                     Comparative                                                                          --   --  --  6.6  --   38.7 30.0 280   x   xx    11.6                  Example 5                                                                     Comparative                                                                          --   --  --  --   41   38.7 30.0 280   xx  xx    79.8                  Example 6                                                                     __________________________________________________________________________     Note:                                                                         *.sup.1 6% aqueous sulfurous acid solution                                    *.sup.2 First grade reagent; product of Wako Junyaku Co.                      *.sup.3 MMA: methyl methacrylate                                              *.sup.4 Cullet deposition:                                                    ⊚ Substantially none;                                          x considerable deposition;                                                    xx plenty of deposition.                                                      Secondary agglomeration:                                                      ⊚ Good, washing and recovery very easy;                        xx poor, washing and recovery very difficult.                            

As is apparent from Table 1, no polymerization activity was observedwhen neither sulfonic acid monomer nor sulfonate monomer was added as inComparative Example 4, and a very low polymerization activity wasobserved in a two-component system comprising a vinyl monomer and asulfonic acid monomer or a sulfonate monomer, whereas the monomerconversion became very high by the addition of an inorganic substance asthe third component according to this invention. On the other hand,although a high monomer conversion was observed, a conventionalpolymerization system containing aqueous sulforous acid, as shown inComparative Example 6, gave a polymerizate markedly inferior in theproblem of cullet deposition and in the ability to form secondaryagglomerates as compared with the present method, indicating that thepracticability of the latter is promising.

EXAMPLES 2 TO 5

The polymerization was carried out in the same manner as in Example 1,except that SPS, AMPS, NaAS or NaMS was used as the sulfonic acidmonomer or sulfonate monomer in place of SEM.Na. In Table 2, are shownthe evaluation results of the monomer conversion in comparison withthose of Example 1.

                                      TABLE 2                                     __________________________________________________________________________                    Inorganic                                                                            Vinyl                                                  Acid monomer    substance                                                                            monomer                                                                            Deionized                                                                           Monomer                                                Amount                                                                             Calcium                                                                              MMA  water conversion                                  Type       (parts)                                                                            sulfite (parts)                                                                      (parts)                                                                            (parts)                                                                             (%)                                         __________________________________________________________________________    Example 1                                                                           SEM.Na                                                                             6.5  38.7   30.0 280   82.6                                        Example 2                                                                           SPS  7.0  "      "    "     80.3                                        Example 3                                                                           AMPS 6.6  "      "    "     72.7                                        Example 4                                                                           NaAS 4.3  "      "    "     44.5                                        Example 5                                                                           NaMS 4.7  "      "    "     41.1                                        __________________________________________________________________________

As is apparent from Table 2, the polymerization activity was very highwith SEM.Na, SPS and AMPS, while somewhat lower with NaAS and NaMS.

About 10 g of each polymer composition obtained in Examples 1 to 5 wasplaced in a cylindrical paper filter and accurately weighed. Usingbenzene, which is a good solvent for the methyl methacrylate polymer, asextraction solvent, the sample was extracted in a Soxhlet extractor for24 hours and the percentage extraction of said polymer composition aswell as [η] of the polymer in the extract were determined. Forcomparison, an inorganic substance (calcium sulfite) was dispersed in asolution of polymethyl methacrylate in methylene chloride by milling andthe solvent was removed by evaporation to obtain a composition in whichthe inorganic substance was covered with polymethyl methacrylate(Comparative Example 7). This composition and the compositions(Comparative Examples 8 and 9) obtained by use of common radicalpolymerization catalysts were tested in a manner similar to thatdescribed above. The results obtained were as shown in Table 3. Thepolymer components of the compositions obtained in Comparative Exampleswere completely extracted in 24 hours of extraction, whereas the polymercomponents of the composite compositions obtained according to thisinvention showed only a small percentage extraction, most part of thepolymer component being resistant to extraction and firmly consolidatedwith calcium sulfite. It is also seen that the polymer components in thecompositions of this invention have far higher [η] values than those ofpolymers obtained by the common procedures.

                                      TABLE 3                                     __________________________________________________________________________                                       Percentage                                                     Monomer        extraction;                                                                         [η]*.sup.2                              Polymerization                                                                             conver-                                                                             Nature of                                                                              benzene, 24                                                                         polymer in                                  procedure*.sup.1                                                                           sion (%)                                                                            polymerizate                                                                           hours (%)                                                                           extract                              __________________________________________________________________________    Example 1                                                                            Present invention,                                                                         82.6  Uniform consoli-                                                                       15    0.485                                       SEN.Na             dation of inorg.                                                              subst. with                                                                   polymer                                             Example 2                                                                            Present invention, SPS                                                                     80.3  Uniform consoli-                                                                       15    0.569                                                          dation of inorg.                                                              subst. with                                                                   polymer                                             Example 3                                                                            Present invention, AMPS                                                                    72.7  Uniform consoli-                                                                       13    0.686                                                          dation of inorg.                                                              subst. with                                                                   polymer                                             Example 4                                                                            Present invention, NaAS                                                                    44.5  Uniform consoli-                                                                       25    0.412                                                          dation of inorg.                                                              subst. with                                                                   polymer                                             Example 5                                                                            Present invention, NaMS                                                                    41.1  Uniform consoli-                                                                       28    0.408                                                          dation of inorg.                                                              subst. with                                                                   polymer                                             Comparative                                                                          Mixing in polymethyl                                                                       --    --       100   0.056                                Example 7                                                                            methacrylate solution*.sup.3                                           Comparative                                                                          Polymerization in                                                                          43.0  Independent pre-                                                                       100   0.059                                Example 8                                                                            aqueous medium with                                                                              sence of inorg.                                            AIBN as initiator  subst. and                                                                    homopolymer                                         Comparative                                                                          Polymerization in                                                                           5.0  Independent pre-                                                                       100   0.053                                Example 9                                                                            aqueous medium with                                                                              sence of inorg.                                            KPS as initiator   subst. and                                                                    homopolymer                                         __________________________________________________________________________     Note:                                                                         *.sup.1 The inorganic substance used was calcium sulfite.                     *.sup.2 As determined at 25° C. in chloroform (0.5% solution).         *.sup.3 Acrypet VH (a product of Mitsubishi Rayon Co.) was used.              AIBN Azobisisobutyronitrile                                                   KPS Potassium persulfate                                                 

EXAMPLE 6

Polymerization was carried out in the same manner as in Example 1,except that various inorganic substances other than the calcium sulfitewere used. The results of evaluation of the compositions obtained wereas shown in Table 4.

                                      TABLE 4                                     __________________________________________________________________________                                           Nature of                                                                     polymerizate                                              Acid Vinyl                                                                              De- Monomer                                                                             Depo-                                                                             2 ry                               Inorganic substance                                                                              monomer                                                                            monomer                                                                            ionized                                                                           con-  sition                                                                            agglo-                                           Amount                                                                             SEM.Na                                                                             MMA  water                                                                             version                                                                             of  mera-                              No.                                                                              Type       (parts)                                                                            (parts)                                                                            (parts)                                                                            (parts)                                                                           (%)   cullet                                                                            tion                               __________________________________________________________________________    1  Calcium sulfate                                                                          38.7 6.5  30.0 280 78.0  ⊚                                                                  ⊚                   2  Silicon dioxide                                                                          "    "    "    "   76.2  ⊚                                                                  ○                           3  Titanium oxide                                                                           "    "    "    "   71.5  ⊚                                                                  ○                           4  Talc       "    "    "    "   80.8  ⊚                                                                  ⊚                   5  Antimony trioxide                                                                        "    "    "    "   79.3  ⊚                                                                  ○                           6  Clay       "    "    "    "   76.6  ⊚                                                                  ⊚                   7  Calcium carbonate                                                                        "    "    "    "   75.1  ⊚                                                                  ○                           8  Aluminum oxide                                                                           "    "    "    "   70.1  ⊚                                                                  ⊚                   9  Carbon black                                                                             "    "    "    "   65.3  ⊚                                                                  ⊚                   10 Nickel powder                                                                            "    "    "    "   83.0  ⊚                                                                  ⊚                   11 Iron powder                                                                              "    "    "    "   81.1  ⊚                                                                  ⊚                   12 Zinc powder                                                                              "    "    "    "   71.0  ⊚                                                                  ○                           13 Copper powder                                                                            "    "    "    "   80.0  ⊚                                                                  ○                           14 Ferric oxide                                                                             "    "    "    "   66.2  ⊚                                                                  ○                           15 Zinc oxide "    "    "    "   61.9  ⊚                                                                  ○                           16 Aluminum hydroxide                                                                       "    "    "    "   42.0  ⊚                                                                  x                                  17 Magnesium oxide                                                                          "    "    "    "   33.2  ⊚                                                                  x                                  18 Calcium hydroxide                                                                        "    "    "    "   30.1  ⊚                                                                  x                                  19 Graphite   "    "    "    "   70.1  ⊚                                                                  ○                           20 Carbon fiber (powder)                                                                    "    "    "    "   85.0  ⊚                                                                  ⊚                   21 Glass fiber (powder)                                                                     "    "    "    "   67.3  ⊚                                                                  ○                           __________________________________________________________________________

As is apparent from Table 4, although the present process showed somedegree of dependence upon the type of inorganic substance, the monomerconversion was generally good. The process was found to be satisfactorywith respect to the deposition of cullet and the secondaryagglomeration, both of which are important problems for thepracticability of the present process.

EXAMPLE 7

Polymerization was carried out in the same manner as in Example 1,except that vinyl monomers shown in Table 5 were used each along or inmixtures in place of the methyl methacrylate. The results of evaluationperformed on the resulting compositions were as shown in Table 5.

                                      TABLE 5                                     __________________________________________________________________________                              Inorganic                                                          Compound containing                                                                      substance                                           Vinyl monomer  sulfonic acid group                                                                      Calcium                                                                            Deionized                                                                           Monomer                                            Amount                                                                             SEM.Na     sulfite                                                                            water conversion                               No.                                                                              Type   (parts)                                                                            (parts)    (parts)                                                                            (parts)                                                                             (%)                                      __________________________________________________________________________    1  ST     30.0 6.5        38.7 280   20.0                                     2  BuA    "    "          "    "     27.8                                     3  MMA/ST*.sup.1                                                                        "    "          "    "     71.5                                     4  MMA/BuA                                                                              "    "          "    "     62.3                                     5  ST/BuA "    "          "    "     22.5                                     __________________________________________________________________________     Note:                                                                         *.sup.1 Mixing ratio of monomers: 50:50 by weight;                            ST: styrene;                                                                  BuA: nbutyl acrylate;                                                         MMA: methyl methacrylate                                                 

EXAMPLE 8

Into a Henschel mixer for milling powders, were charged 38.7 g ofcalcium sulfite and 6.5 g of SEM.Na. The mixture was thoroughly stirredfor 10 minutes and suspended in 280 ml of deionized water to form adispersion in a reactor provided with auxiliaries as in Example 1. Tothe resulting filler mixture, after flushing with nitrogen for 30minutes, was added with vigorous stirring 30.0 g of methyl methacrylate,used as vinyl monomer, under a stream of nitrogen. The reactant mixturewas heated to 50° C. in a water bath and allowed to polymerize at thesame temperature for 8 hours. After completion of the polymerization, asample was withdrawn and evaluated as in Example 1. It was found thatthe monomer conversion was 72.1%, and the resulting polymer compositionhas a structure such that the surface of the inorganic substance wasuniformly and firmly covered with the consolidated polymer of saidmonomer.

EXAMPLE 9 AND COMPARATIVE EXAMPLES 10 TO 13

In a 500-ml four-necked flask provided with a condenser, nitrogen inlet,stirrer and a thermocouple four detecting the internal temperature, 38.7g of calcium sulfite hemihydrate, used as the inorganic substance, wassuspended in 280 ml of deionized water to form a dispersion. Afterflushing the flask with nitrogen for 30 minutes, 30.0 g of methylmethacrylate, used as the vinyl monomer, was added to the dispersionwith vigorous stirring under a nitrogen stream. The reactant mixture washeated to 50° C. in a water bath. After confirming the uniformdispersion of the added monomer, to the dispersion was added slowly 2.0g of commercially available special grade acrylic acid, used as thecarboxylic acid-type monomer. The mixture was maintained at the sametemperature to allow the polymerization to proceed for 8 hours. Aftercompletion of the polymerization, about 2 g of the reaction mixture waswithdrawn as a sample. The sample was tested for the conversion bydetermining the remained unreacted monomer by gas chromatography usingdioxane as internal standard. For comparison, similar polymerizationprocedure and similar evaluation tests on the polymerization mixture tothose described above were repeated without adding the inorganicsubstance or the carboxylic acid-type monomer.

The results obtained were as shown in Table 6, wherein all parts are byweight.

                                      TABLE 6                                     __________________________________________________________________________                            Inorganic                                                    Carboxylic acid-type monomer                                                                   substance                                                                          Vinyl     Monomer                                       Acrylic                                                                            Methacrylic                                                                          Crotonic                                                                           Calcium                                                                            monomer                                                                           Deionized                                                                           conver-                                       acid acid   acid*.sup.1                                                                        sulfite*.sup.2                                                                     MMA water sion                                          (parts)                                                                            (parts)                                                                              (parts)                                                                            (parts)                                                                            (parts)                                                                           (parts)                                                                             (%)                                    __________________________________________________________________________    Example 9                                                                            2.0  --     --   38.7 30.0                                                                              280   81.1                                   Comparative                                                                   Example 10                                                                           2.0  --     --   --   30.0                                                                              280   7.2                                    Comparative                                                                   Example 11                                                                           --   2.6    --   --   30.0                                                                              280   7.6                                    Comparative                                                                   Example 12                                                                           --   --     2.6  --   30.0                                                                              280   7.0                                    Comparative                                                                   Example 13                                                                           --   --     --   38.7 30.0                                                                              280   0.0                                    __________________________________________________________________________     Note:                                                                         *.sup.1 CH.sub.3 CH═CHCO.sub.2 H                                          *.sup.2 First grade reagent (Wako Junyaku Co.)                                MMA Methyl methacrylate                                                  

As is apparent from Table 6, no polymerization activity was observedwhen the carboxylic acid-type monomer was not added as in ComparativeExample 13 and a low activity was observed in a two-component systemcomprising a vinyl monomer and a carboxylic acid-type monomer, whereasthe monomer conversion became very high by the addition of an inorganicsubstance as the third component according to this invention, indicatingpromising practicability of this invention.

EXAMPLES 10 TO 14 AND COMPARATIVE EXAMPLES 14 TO 16

Polymerization was carried out in the same manner as in Example 9,except that methacrylic acid, crotonic acid, tiglic acid, cinnamic acid,or maleic anhydride was used as the carboxylic acid-type monomer inplace of the acrylic acid. The results of determination of monomerconversions and evaluation of the polymer compositions were as shown inTable 7.

                                      TABLE 7                                     __________________________________________________________________________                       Inorganic           Nature of poly-                        Carboxylic acid-   substance                                                                          Vinyl                                                                              DE- Monomer                                                                             merizate                               type monomer       Calcium                                                                            monmer                                                                             ionized                                                                           conver-                                                                             Cullet                                                                            2 ry                               Example       Amount                                                                             sulfite                                                                            MMA  water                                                                             sion  depo-                                                                             agglome-                           No.  Type     (parts)                                                                            (parts)                                                                            (parts)                                                                            (parts)                                                                           (%)   sition                                                                            ration                             __________________________________________________________________________     9   Acrylic acid                                                                           2.0  38.7 30.0 280 81.1  ⊚                                                                  ⊚                   10   Methacrylic acid                                                                       2.6  "    "    "   88.5  ⊚                                                                  ⊚                   11   Crotonic acid                                                                          2.6  "    "    "   80.0  ○                                                                          ○                           12   Tiglic acid*.sup.1                                                                     3.0  "    "    "   62.3  ○                                                                          Δ                            13   Cinnamic acid*.sup.2                                                                   4.4  "    "    "   57.6  ○                                                                          Δ                            14   Maleic anhydride                                                                       2.9  "    "    "   61.0  ○                                                                          Δ                            __________________________________________________________________________     Note:                                                                         *.sup.1 CH.sub.3 CH═C(CH.sub.3)CO.sub.2 H                                 *.sup.2 C.sub.6 H.sub.5 CH═CHCO.sub.2 H                              

As is apparent from Table 7, acrylic acid, methacrylic acid and crotonicacid showed high polymerization activities, while tiglic acid, cinnamicacid and maleic anhydride showed polymerization activities at somewhatlower levels; similar tendencies were observed in the cullet depositionand secondary agglomeration, both of which are important factors for thecommercialization of the process.

About 10 g of each polymer composition obtained in Examples 9 to 14 wasplaced in a cylindrical paper filter and accurately weighed. usingbenzene, which is a good solvent for the polymethyl methacrylate, asextraction solvent, the sample was extracted in a Soxhlet extractor for24 hours and the percentage extraction of said polymer composition and[η] of the polymer in the extract were determined. For comparison, apowdered inorganic substance (calcium sulfite) was dispersed in asolution of polymethyl methacrylate in methylene chloride by milling andthe solvent was removed by evaporation to obtain a composition in whichthe inorganic substance was covered with polymethyl methacrylate(Comparative Example 14). This composition and the compositions(Comparative Examples 15 and 16) obtained by common radicalpolymerization were tested in a manner similar to that described above.The results obtained were as shown in Table 8. The polymer components ofthe compositions obtained in Comparative Examples were completelyextracted in 24 hours of extraction, whereas the polymer components ofthe composite compositions obtained according to this invention showedonly a small percentage extraction, most part of the polymer componentbeing resistant to extraction and firmly consolidated with calciumsulfite. It is also seen that the polymer components in the compositionsof this invention have far higher [η] values than those of polymersobtained by the common polymerization procedures.

                                      TABLE 8                                     __________________________________________________________________________                                      Percentage                                                    Monomer         extraction,                                                                         [η]*.sup.2 of                            Polymerization                                                                           conver-                                                                             Nature of benzene, 24                                                                         polymer in                                   procedure*.sup.1                                                                         sion (%)                                                                            polymerizate                                                                            hours (%)                                                                           extract                               __________________________________________________________________________    Example 9                                                                            Present invention,                                                                       81.1  Uniform consolida-                                                                      12    0.491                                        acrylic acid     tion of inorg.                                                                subst. with                                                                   polymer                                               Example 10                                                                           Present invention,                                                                       88.5  Uniform consolida-                                                                      12    0.477                                        methacrylic acid tion of inorg.                                                                subst. with                                                                   polymer                                               Example 11                                                                           Present invention,                                                                       80.0  Uniform consolida-                                                                      14    0.523                                        crotonic acid    tion of inorg.                                                                subst. with                                                                   polymer                                               Example 12                                                                           Present invention,                                                                       62.3  Uniform consolida-                                                                      19    0.405                                        tiglic acid      tion of inorg.                                                                subst. with                                                                   polymer                                               Example 13                                                                           Present invention,                                                                       57.6  Uniform consolida-                                                                      21    0.410                                        cinnamic acid    tion of inorg.                                                                subst. with                                                                   polymer                                               Example 14                                                                           Present invention,                                                                       61.0  Uniform consolida-                                                                      20    0.415                                        maleic anhydride tion of inorg.                                                                subst. with                                                                   polymer                                               Comparative                                                                          Mixing in polymethyl                                                                     --     --       100   0.056                                 Example 14                                                                           methacrylate solu-                                                            tion*.sup.3                                                            Comparative                                                                          Polymerization in                                                                        43.0  Independent                                                                             100   0.059                                 Example 15                                                                           aqueous medium with                                                                            presence of inorg.                                           AIBN as initiator                                                                              subst. and homo-                                                              polymer                                               Comparative                                                                          Polymerization in                                                                         5.0  Independent                                                                             100   0.053                                 Example 16                                                                           aqueous mesium with                                                                            presence of inorg.                                           KPS as initiator subst. and homo-                                                              polymer                                               __________________________________________________________________________     Note:                                                                         *.sup.1 The inorganic substance used was calcium sulfite.                     *.sup.2 As determined at 25° C. in chloroform (0.5% solution).         *.sup.3 Acrypet VH (a product of Mitsubishi Rayon Co.) was used.              AIBN Azobisisobutyronitrile                                                   KPS Potassium persulfate                                                 

EXAMPLE 15

Polymerization and evaluation of the resulting compositions were carriedout in the same manner as in Example 9, except that various inorganicsubstances were used in place of the calcium sulfite. The resultsobtained were as shown in Table 9.

                                      TABLE 9                                     __________________________________________________________________________                                           Nature of                                                 Acid                polymerizate                                              monomer                                                                            Vinyl                                                                              De- Monomer                                                                             Depo-                                                                             2 ry                               Inorganic substance                                                                              Acrylic                                                                            monomer                                                                            ionized                                                                           con-  sition                                                                            agglo-                                           Amount                                                                             acid MMA  water                                                                             version                                                                             of  mera-                              No.                                                                              Type       (parts)                                                                            (parts)                                                                            (parts)                                                                            (parts)                                                                           (%)   cullet                                                                            tion                               __________________________________________________________________________    1  Calcium sulfate                                                                          38.7 2.0  30.0 280 79.1  ⊚                                                                  ○                           2  Silicon dioxide                                                                          "    "    "    "   80.0  ⊚                                                                  ○                           3  Titanium oxide                                                                           "    "    "    "   78.9  ⊚                                                                  ○                           4  Talc       "    "    "    "   83.5  ⊚                                                                  ○                           5  Antimony trioxide                                                                        "    "    "    "   76.2  ⊚                                                                  ○                           6  Clay       "    "    "    "   81.3  ○                                                                          ○                           7  Calcium carbonate                                                                        "    "    "    "   80.5  ○                                                                          x                                  8  Aluminum oxide                                                                           "    "    "    "   72.7  ⊚                                                                  ○                           9  Carbon black                                                                             "    "    "    "   68.0  ⊚                                                                  ○                           10 Nickel powder                                                                            "    "    "    "   81.0  ○                                                                          ○                           11 Iron powder                                                                              "    "    "    "   80.3  ○                                                                          ○                           12 Zinc powder                                                                              "    "    "    "   78.8  ⊚                                                                  ○                           13 Copper powder                                                                            "    "    "    "   71.4  ○                                                                          ○                           14 Ferric oxide                                                                             "    "    "    "   83.0  ○                                                                          ○                           15 Zinc oxide "    "    "    "   70.0  ○                                                                          ○                           16 Aluminum hydroxide                                                                       "    "    "    "   71.9  Δ                                                                           Δ                            17 Magnesium oxide                                                                          "    "    "    "   58.1  Δ                                                                           x                                  18 Calcium hydroxide                                                                        "    "    "    "   43.6  Δ                                                                           Δ                            19 Graphite   "    "    "    "   71.1  ○                                                                          ○                           20 Carbon fiber (powder)                                                                    "    "    "    "   80.0  ⊚                                                                  ⊚                   21 Glass fiber (powder)                                                                     "    "    "    "   62.1  ○                                                                          ○                           __________________________________________________________________________

As is apparent from Table 9, although with respect to the polymerizationactivity the present process showed some degree of dependence upon thetype of inorganic substance, the monomer conversion was generally good.The process was found to be satisfactory with respect to the depositionof cullet and the secondary agglomeration, both of which are importantfactors for the practicability of the present process.

EXAMPLE 16

Polymerization was carried out in the same manner as in Example 9,except that vinyl monomers shown in Table 10 were used each alone or inmixtures in place of the methyl methacrylate. The results of evaluationperformed on the resulting composition were as shown in Table 10.

                  TABLE 10                                                        ______________________________________                                                                 In-                                                                   Acid    organic                                                               mono-   sub-                                                                  mer     stance        Mono-                                                   Acry-   Cal-    De-   mer                                    Vinyl monomer    lic     cium    ionized                                                                             con-                                                   Amount   acid  sulfite                                                                             water version                            No.  Type       (parts)  (parts)                                                                             (parts)                                                                             (parts)                                                                             (%)                                ______________________________________                                        1    ST         30.0     2.0   38.7  280   26.7                               2    BuA        "        "     "     "     33.9                               3    MMA/ST*.sup.1                                                                            "        "     "     "     79.1                               4    MMA/BuA    "        "     "     "     70.0                               5    ST/BuA     "        "     "     "     28.1                               ______________________________________                                         Note:                                                                         *.sup.1 Mixing ratio of monomers: 50:50 by weight.                            ST: styrene;                                                                  BuA: nbutyl acrylate;                                                         MMA: methyl methacrylate.                                                

EXAMPLE 17

Into a Henschel mixer for milling powders, were charged 38.7 g ofcalcium sulfite and 2.0 g of acrylic acid. The mixture was thoroughlystirred for 10 minutes and suspended in 280 ml of deionized water toform a dispersion in a reactor provided with auxiliaries as inExample 1. To the resulting filler mixture, after flushing with nitrogenfor 30 minutes, was added with vigorous stirring 30.0 g of methylmechacrylate, used as vinyl monomer, under a stream of nitrogen. Thereactant mixture was heated to 50° C. in a water bath and allowed topolymerize at the same temperature for 8 hours. After completion of thepolymerization, a sample was found that the monomer conversion was76.8%, and the resulting polymer composition has a structure such thatthe surface of the inorganic substance was uniformly and firmly coveredwith the consolidated polymer of said vinyl monomer.

EXAMPLE 18

The polymer compositions according to this invention were blended withpellets of general purpose polymers and the inorganic substance contentwas adjusted to 30%. A molded article of the composite composition wasprepared from each blend by means of an extruder and evaluated for theprocessability, dispersibility, gloss and mechanical characteristics.For comparison, a blend of the polymer and the untreated inorganicsubstance (referred to as simple blend in Table 11) and a blend of thepolymer composition obtained by using an aqueous sulfurous acid asinitiator (referred to as H₂ SO₃ initiated in Table 11) were preparedand tested likewise. The results were as shown in Table 11.

                                      TABLE 11                                    __________________________________________________________________________              Composite     Processability                                                                             Mechanical                                         composition   and appearance                                                                             characteristics                                           Polymer     Disper- Tensile                                                                            Izod impact                                   Inorganic                                                                            being  Process-                                                                           sibili- strength                                                                           resistance                                    substance                                                                            blended                                                                              ability                                                                            ty  Gloss                                                                             (kg/cm.sup.2)                                                                      (kg · cm/cm.sup.2)         __________________________________________________________________________    SEM.Na--initiated                                                                       CaSO.sub.3.1/2H.sub.2 O                                                              Acrypet VH                                                                           ⊚                                                                   ⊚                                                                  ⊚                                                                  563  8.9                                 Acrylic acid-                                                                           "      "      ○                                                                           ○                                                                          ○                                                                          501  7.0                                 initiated                                                                     Simple blend                                                                            "      "      x    #   x   398  3.9                                 H.sub.2 SO.sub.3 --initiated                                                            "      "      x    #   x   401  4.0                                 SEM.Na--initiated                                                                       Talc   Nylon 6*                                                                             ⊚                                                                   ⊚                                                                  ⊚                                                                  803  23.2                                Acrylic acid-                                                                           "      "      ○                                                                           ○                                                                          ○                                                                          750  20.0                                initiated                                                                     Simple blend                                                                            "      "      x    Δ                                                                           x   673  16.1                                H.sub.2 SO.sub.3 --initiated                                                            "      "      x    #   x   691  12.5                                __________________________________________________________________________     Note:                                                                         (1) *T803, a product of Toyobo Co.                                            (2) Evaluation for the processability and the appearance was performed as     follows:                                                                      Processability:                                                               ⊚ No emission of particulates; grabbed by the extruder         screw while maintaining the condition of uniform blend with polymer           pellets.                                                                      ○ Moderate emission of particulates; grabbed by the extruder screw     while maintaining the condition of uniform blend with polymer pellets.        x Emission of plenty of particulates; grabbed by the extruder screw in th     form of nonuniform mixture of the polymer pellets and the inorganic           substance.                                                                    Dispersibility:                                                               ⊚ No fisheye in the extruded strand.                           ○ Scarcely any fisheye in the extruded strand.                         Δ Moderate number of fisheyes in the extruded strand.                   # A great number of fisheyes in the extruded strand.                          Gloss:                                                                        ⊚ Specular gloss (JIS Z 8741) >Gs(60°) 31               ○ Specular gloss (JIS Z 8741)  Gs(60°) 16-30                    x Specular gloss (JIS Z 8741) <Gs(60°) 15                         

As is apparent from Table 11, the polymer composition of this inventionis excellent in practically important performance characteristics suchas processability and appearance and mechanical properties of shapedarticles.

What is claimed is:
 1. A method of preparing a polymeric composition inwhich an inorganic substance is firmly consolidiated in an organicpolymer, comprising: heterogeneously polymerizing methylmethacrylate ora vinyl monomer mixture comprising methylmethacrylate as the majorcomponent without initiating the reaction with a radical polymerizationinitiator at a temperature such that substantially no thermalpolymerization occurs in a polymerization system containing saidinorganic substance dispersed in an aqueous medium in the presence of atleast one monomer selected from the group consisting of sulfonic acidmonomers and sulfonate monomers of formula [I] ##STR9## wherein R₁ ishydrogen, alkyl of 1 to 20 carbon atoms, phenyl, a derivative of aphenyl group, or a halogen atom; X is CONH, ##STR10## COO(CH₂)_(m) or(CH₂)_(n) wherein R₂ and R₃ are each hydrogen or alkyl of 1 to 15 carbonatoms, R₄ is an alkylene group of 1 to 15 carbon atoms, m is an integerof 1 to 20, and n is 0 or an integer of 1 to 20; and U is a hydrogenatom, ammonium radical or an alkali metal atom.
 2. The method of claim1, wherein the sulfonic acid monomer or sulfonate monomer is2-acrylamido-2-methylpropanesulfonic acid, sodium2-methacryloylethanesulfonate, or sodium 3-methacryloylpropanesulfonate.3. The method of claim 1, wherein the inorganic substance is at leastone member selected from the group consisting of calcium sulfite,calcium sulfate, silicon dioxide, titanium oxide, antimony trioxide,talc, clay, aluminum oxide, calcium carbonate, carbon black, carbonfiber, glass fiber, graphite, nickel powder, iron powder, zinc powder,copper powder, iron oxide, zinc oxide and aluminum hydroxide.
 4. Themethod of claim 1, wherein the weight ratio of monomer mixture to theinorganic substance ranges from 250:1 to 1:5.
 5. The method of claim 1,wherein said polymerization reaction is conducted under an inert gasatmosphere at a temperature from 10° to 100° C.
 6. The method of claim1, wherein the amount of said sulfonic acid monomer or sulfonate monomerin the reaction medium ranges from 0.05 to 100% by weight based on thetotal amount of inorganic substance and monomer in the polymerizationmedium.